Andrea Nick, Rockie Mweene & Roland Bäumle
Groundwater Resources of the
Mwembeshi and Chongwe Catchments,
including the Lusaka Region
A Manual of the Hydrogeological Maps
and the Vulnerability Map
Lusaka - Hannover 2012
Prepared as a technical co-operation project
between the governments of the Republic Zambia and
the Federal Republic of Germany
REPUBLIC OF ZAMBIA
Ministry of Mines, Energy and Water Development
Lusaka, Zambia
Federal Institute for Geosciences and Natural Resources
Geozentrum Hannover
Stilleweg 2, 30655 Hannover, Germany
This publication was produced under the technical co-operation project between the Governments of
Zambia and the Federal Republic of Germany implemented by the Department of Water Affairs,
Ministry of Mines, Energy and Water Development, Zambia and the Federal Institute for Geosciences
and Natural Resources, Germany. It complements the hydrogeological map sheet series for the Mwembeshi and Chongwe catchments.
Text, layout and graphics: Department of Water Affairs, Lusaka
Photographs: Roland Bäumle (cover b, c, d; p. 14), Kai Hahne (p. 3), Torsten Krekeler (cover a, p. 3),
Robert Kringel (p. 1 & 3), Christoph Mayerhofer (p. 3), Christoph Neukum (p. 11),
Andrea Nick (p. 3 & 14)
Print Layout: Mariola Kosenko, Andrea Nick
Printed by:
Printech Ltd, Lusaka
All rights reserved. No part of this publication may be reproduced, stored in any retrieval system or
transmitted in any form or by any means, electronical, mechanical, photocopying, recording or otherwise, without the written permission of the copyright owners.
©2012 Department of Water Affairs, Lusaka & Federal Institute for Geosciences and Natural Resources,
Hannover
First Edition, February 2012
Table of Contents
1. Groundwater Information System
5
2. The Hydrogeological Maps
9
2.1. Coverage
9
2.2. Map elements
10
2.3. Content of Main Map
12
2.3.1 Hydrology
12
2.3.2 Geology
13
2.4. Inset maps
3. The Vulnerability Map
20
21
3.1. Coverage
21
3.2. Content of Main Map
21
3.2.1 Risk Areas
21
3.2.2 Vulnerability
21
3.3. Inset Maps
4. References
22
23
1. Groundwater Information System
The hydrogeological maps at hand are
based on data which is stored and managed in a groundwater information system.
The groundwater information system as
described in reports [2] and [3] consists of:
of the Department of Water Affairs. The
individual fields often work with dropdown
lists to facilitate a quick data entry and to prevent spelling mistakes.
1. The groundwater database
2. The Geographic Information System (GIS)
Table 1: Type of information held in the GeODin
database.
General information
Groundwater Database
Location
Water Point name and number
Geographic coordinates
Elevation
Location with regard to drainage
catchment
Location with regard to administrative/political unit
Drilling
Drilling/completion dates
Drilling contractor
Water point funding
Status
Type and purpose of water point
usage
The groundwater database was established
using the commercial software package
GeODin®. The software is based on a MSAccess database but provides user-friendly data
input masks as shown for instance in the
Figure 1.
Hydraulics
Aquifer
Borehole and aquifer depth and
thickness
Aquifer type
Static water levels (single values or
time-series)
Hydraulic
(Pump-)
testing
Hydraulic test summary
Hydraulic test data
Hydraulic characteristics (yield,
permeability)
Borehole profile
Figure 1: Data input mask for entering a new
water point into the GeODin groundwater database. Detail shows, as an example, how available
sub-catchments within Middle Zambezi River Basin
can be selected from a dropdown list.
Geology
Lithological and stratigraphical log
Design
Position of casing, screens, etc.
Groundwater quality
Chemistry
The individual input masks were modified
to meet the specific needs and requirements
Water analyses results
Comparisons to drinking water
standards
Water quality classification
5
Figure 2: Example of a borehole description exported from the GeODin database for the borehole in Lusaka’s
Cooperative College, Water-Point No. 5040939 in Lusaka District.
6
The software also offers various possibilities
to query, export, display and visualize groundwater related data entered (e.g. selected data
tables, borehole completion reports, lithological borehole logs, etc). An example for a borehole design with geological description is given
in Figure 2.
The database contains information on more
than 2,500 water points found in Lusaka and
its surroundings including boreholes, handdug wells, unsuccessful drillings and springs.
The data compilation combines general
information (e.g. location, type and purpose of
water point) with comprehensive and detailed
technical information on groundwater hydraulics, borehole design, as well as geology and
groundwater quality (Table 1).
GIS
The GIS includes individual digital map layers
containing topographic, geological, hydrological and groundwater related information. The
map layers are seamless, i.e. not bounded by
the margins of the original map sheets. The GIS
layers can be combined for the compilation of
various thematic maps or applied to further
geo-related applications and analysis.
Table 2 Composition of water point number.
Digit
No.
Value
1
“5” for Lusaka Province
“1” for Central Province
2 and “01“ for Chongwe/Chibombo District
3
“02“ for Kafue/Kabwe District
“03“ for Luangwa/Kapiri-Mposhi District
“04“ for Lusaka/Mkushi District
“05“ for Mumbwa District
“06“ for Serenje District
4 to
7
Indexed numbers ranging from
1 to 9999
To water points located in Chongwe District,
for example, numbers ranging from 5010001
to 5019999 can be given out. Accordingly,
numbers ranging from 1010001 to 1019999
and from 5040001 to 5049999 represent
water points in Chibombo District in Central
Province and Lusaka District in Lusaka Province, respectively.
Water Point Number
For reasons of structuring the database a
water point numbering system had to be introduced. Each water point number is unique, i.e.
can only be allocated to one point. The number is composed of seven digits with the first
digit representing the Province (e.g. “5” for the
Lusaka Province), the second and third given
out according to the District and the remaining four digits specifying the individual water
points.
7
2. The Hydrogeological Maps
2.1. Coverage
The hydrogeological map series developed for the
Mwembeshi and Chongwe catchments include
one sheet at scale 1:250,000 and one sheet at
scale 1:75,000 (Figure 3, incl. Southern Province
maps). Additionally, a groundwater vulnerability
map at scale 1:75,000 was produced. The maps
are designed to display groundwater features at
catchment and sub-catchment scale. The contents of the maps comprise:
 Topography including roads, villages,
towns, health centres and schools,
 Hydrography including rivers and
wetlands,
Figure 3: Available hydrogeological map sheets:
1. Northern Kariba Lake and Kafue Gorge
2. Kafue Flats and Southern Tributaries
3. Southern Kariba Lake and Kalomo
 Surface elevation,
 Surface catchment and sub-catchment
boundaries,
 Water points such as boreholes and wells,
including unsuccessful drilling sites, and
thermal springs,
 Lithology and geological structures (faults,
etc),
 Boundaries and potential of groundwater
systems, so-called aquifers,
 Groundwater elevation contours and direction of groundwater flow,
 Rainfall distribution (Inset map).
4. Mwembeshi and Chongwe Catchments
5. Lusitu River
6. Lusaka and surroundings.
9
2.2. Map elements
Each map sheet consists of the following elements (Figure 4):
Main map (body)
 a cover page with the map title and institutional logos, etc.,
The “map body” shows the main theme
of the map for the selected map area. The
main theme of the hydrogeological map is,
of course, groundwater. Other examples of
thematic maps are maps showing climate, vegetation, natural resources, population density,
economic activity, etc.
 the body of the main map,
 a map legend,
 a frame consisting of neatline(s) and grid,
 a scale and scale bar,
 inset map(s) and
 marginal text.
Figure 4: Main components of the hydrogeological maps.
10
Legend
The “map legend” or “map key” explains the
map symbols used on the map and what
objects or features (e.g. town, river, district,
etc.) they represent. Map symbols are made
of cartographic elements like points, lines and
polygons.
Scale and scale bar
The “map scale” indicates the relationship
between a certain distance on the map and the
actual distance on the ground. A “large” scale
map refers to one which shows greater detail.
A graphic scale such as a scale bar can be used
to determine distances on the ground along
with a ruler. A word statement gives a written
description of the map distance. For the maps
at scale 1:250,000 and 1:75,000 this statement
is “1 centimetre equals 2.5 kilometres“ and
“1 centimetre equals 750 metres“, respectively.
An example of the scale, scale bar and the corresponding word statement is given below:
Figure 5: Scale and scale bar.
Neatlines and grid
Neatlines are used to frame the map and to
indicate exactly where the area of a map
begins and ends. The numbers next to the
neatlines represent “world” coordinates of the
geographic coordinate system and “metric”
coordinates (easting and southing) corresponding to the projected coordinate system.
The system of latitudes and longitudes form
the “geographical graticule” whereas the network of lines connecting the metric coordinates is referred to as the map “grid”.
For the examples indicated in Figure 6 the
geographic coordinates indicate an area 28
degrees east of the prime meridian (0 degree)
which, by definition, passes through Greenwich (near London) and 16 degrees 30 minutes
south of the Equator.
The map projection applied is based on
the Transverse Mercator system using the
27 degrees East line as the central meridian. By definition, a value of 500,000 meters
(“false easting”) and of 10,000,000 meters
(“false nothing”) is given to the central meridian and the Equator, respectively, in order to
avoid negative values. Easting and southing
indicate the position of a location in relation
Figure 6: Neatline, graticule and grid.
to the central meridian and the Equator. In
the examples given, the coordinates define an
area approximately 100,000 m (600,000 minus
500,000 metres) east of the central meridian and 1,720,000 metres (10,000,000 minus
8,280,000 metres) south of the Equator.
Marginal Text
The additional text section includes the
author’s and cartographer’s names, map projection details, disclaimers, source of data, etc.
11
2.3. Content of Main Map
2.3.1 Hydrology
cal maps. The symbols represent dams, lakes,
lagoons, reservoirs; swamps or marshes; pans;
dambos; and main river areas (Figure 8).
The hydrology displays surface water bodies
and boundaries. Surface water features include
lakes, dams, wetlands as well as rivers and river
catchments.
Rivers
The map symbology distinguishes perennial
rivers from intermittent or seasonal rivers
(Figure 7).
Figure 8: Map symbols for various types of wetlands (scale 1:250,000).
Additional hydrology features included in the
hydrogeological map scale 1:75,000 comprise
sewer stabilization ponds and open groundwater surfaces as frequently encountered in
quarries (Figure 9):
Figure 7: Map symbols for water courses.
A river or stream that flows all year round is
called perennial.
A seasonal river or stream flows only during
the rainy season and dries out during the dry
season.
A river or stream is called intermittent if runoff is subject to interruption depending on the
amount and duration of rainfall. The flow of
intermittent rivers lasts over longer periods
compared to ephemeral rivers, which are
mostly dry and subject to water flow for only
short periods (hours to a few days) after heavy
rainfalls.
Wetlands
Wetlands cover more than 20% of Zambia’s
total area [1]. Five different symbol classes
for wetlands are used in the hydrogeologi-
12
Figure 9: Additional map symbols for “wetlands”
(scale 1:75,000).
In geography, a marsh is a type of wetland
which is subject to frequent or continuous
inundation. A marsh is different from a swamp,
in that it has a smaller proportion of open
water surface, and is generally shallower than
a swamp.
A pan is a depression without drainage outlet
where water pools seasonally.
Dambos have been defined as “seasonally
waterlogged, predominantly grass covered,
depressions bordering headwater drainage
lines” [7]. The term for this complex type of
shallow wetland is used in central, southern
and eastern Africa, particularly in Zambia and
Zimbabwe.
2.3.2. Geology
Lithology
Figure 10: Dambo surrounded by woodland.
The treeless grass covered depression is seasonally waterlogged by seepage from surrounding high ground assisted by rainfall and
has shallow water tables (<1 m) for most part
of the year [1]. The vegetation of dambos is
characterised by grasses, rushes, sedges and
the lack of trees, contrasting with surrounding woodland such as miombo woodland
(Figure 10).
Catchments
A catchment or drainage basin is the land area
that is drained by a river or river system.
The catchment boundaries in the map refer to
the main river systems and basins (Figure 11).
The lithology describes the rock type and its
composition. The maps distinguish between
about a dozen different types of lithology.
Sedimentary, igneous and metamorphic rocks
together form the three major groups of rock.
Sedimentary rock is formed by the deposition
and compaction of mineral grains or materials from living organisms, or by chemical precipitation. Sedimentary rocks include among
others limestone, dolomite, conglomerate,
sandstone and shale.
Igneous rock is a rock solidified from cooled
magma. It is called extrusive if formed at the
earth’s surface or intrusive if the magma cools
and solidifies underneath the surface. Typical
examples for extrusive and intrusive igneous
rocks are basalt and granite.
Figure 11: Map symbols for catchment boundaries.
Metamorphic rock is a rock derived from preexisting rock, of either sedimentary or igneous
origin that was transformed in response to
marked changes in temperature and pressure
usually at considerable depth under the Earth’s
surface. Metamorphic rocks include among
others marble, gneiss and schist.
According to the National Water Resources
Master Plan [9], six such basins and river systems can be distinguished in Zambia, namely
the Zambezi Main, Kafue, Luangwa, Chambeshi
and Luapula rivers and the Lake Tanganyika
basin. The Zambezi Main river was further
divided in the Upper Zambezi defined as the
drainage area upstream the Victoria Falls, and
the Middle Zambezi drainage area.
Figure 12: Map symbols for various types of lithology.
Catchment boundary lines displayed on the
maps separate the Kafue and Luangwa catchments from the Upper and Middle Zambezi
Main catchments. Sub-Catchment boundaries
delineate the river drainage areas of smaller
tributaries to the Kafue, Luangwa and Zambezi
Main rivers.
Three examples for map symbols used to display lithological characteristics in the maps are
shown in Figure 12.
13
Tectonic lineaments
A fault is a fracture or a zone of fractures along
which there has been displacement of the sides
relative to each other. In rocks with little primary porosity (voids) faults may constitute
major pathways for underground water flow.
Figure 13: Map symbols for faults.
pump, submersible pump, bucket and windlass
or windmill. Finally, the maps show natural
occurrences of hot (thermal) springs.
On the 1:75,000 scale map the water points
are labelled with the water point number
(see Chapter 1). There are some features
in the 1:75,000 scale map which do not
appear on the 1:250,000 scale map. These are
listed in the following. All mapped springs are
distinguished by their flows being perennial
(constantly flowing) or seasonal/intermittent
(flows only during the rainy season or from
time to time) as presented in Figure 15.
Inferred faults are faults that cannot be
detected on the surface. Instead, their position
was derived from geological interpretation.
2.3.3. Groundwater Features
Water Point Information
Individual map symbols are used to differentiate between the various water point types
(Figure 14). Boreholes are thus distinguished
from shallow hand dug wells. The symbols also
denote the type of installation such as hand-
Figure 15: Map symbol for springs.
Furthermore, water points serving as monitoring boreholes carry the symbol depicted in
Figure 16.
Figure 16: Map symbol for monitoring boreholes.
Production wells of the water supply utility are
shown on the 1:75,000 scale map using the
symbols given in Figure 17.
Figure 17: Map symbol for production boreholes.
Figure 14: Map symbols allocated to the various
water point types.
14
Examples for wells in rural areas and production boreholes used for municipal water supply are presented in Figure 18 and Figure 19,
respectively.
Figure 18: The two most common water point types: Handpump of type India Mark II (left) and hand dug well
with bucket and windlass (right).
Figure 19: Municipal water supply wells in Lusaka.
Groundwater Potential
In the hydrogeological maps, the groundwater
systems were grouped in six classes (or “categories”) according to their potential. Rocks that
are water saturated and sufficiently permeable
to store and transmit groundwater are called
“aquifers”.
The applied distinction of aquifer classes
was adopted from the method proposed by
Struckmeyer and Margat [8]. The classification
combines information on aquifer potential
(productivity and lateral extent) and the type
of groundwater flow regime (intergranular or
fissured).
15
A scheme of areal colours was developed to
represent hydrogeological characteristics in
the maps. The colouring scheme is illustrated
in Figure 20 as a triangle in which the potential is decreasing from top to bottom. Dark
blue and dark green colours represent aquifers
with high potential. Light blue and light green
colours represent aquifers with moderate
potential. Formations with limited potential
are coloured in light brown while strata with
essentially no groundwater are in dark brown.
For groundwater systems with high or moderate potential the colouring scheme also
considers the dominant type of groundwater
flow within the rock. Blue colours are used for
systems in which flow is mainly intergranular
Figure 20: Aquifer classification system (after [8]).
16
while green colours represent systems formed
by hard rock, including karst rock, in which
flow occurs in fissures, fractures or dissolution
cavities (see box “Groundwater Flow Regimes”
for more details).
An attempt was made to give practical examples for the possible use of the groundwater resources for each category (Table 3, last
column). Aquifers with a high potential (categories A and C) for example may permit withdrawals of regional importance such as supply
to major towns or large-scale irrigation. Aquifers with limited potential (category E) should
suffice for the supply of water to rural villages
with a handpump.
Table 3: Hydraulic characterisation of the aquifer categories (modified after [6], [8]). See box “Hydraulic
Characteristics of Aquifers” for an explanation of the listed parameters.
Aquifer
Category
A ,C
Specific
Capacity
[L/s/m]
>1
Transmissivity
Hydraulic
[m2/d]
conductivity
[m/d]
> 75
>3
Very approx.
expected yield
[L/s]
> 10
Groundwater Potential
High:
Withdrawals of regional
importance (supply to
towns, irrigation)
B, D
0.1 – 1
5 – 75
0.2 – 3
1 – 10
Moderate:
Withdrawals for local
water supply (smaller
communities, small-scale
irrigation etc.)
E
0.001 – 0.1
0.05 – 5
0.002 – 0.2
0.01 – 1
Limited:
Smaller withdrawals for
local water supply (supply
through handpump, private consumption)
F
< 0.001
< 0.05
< 0.002
< 0.01
Essentially none:
Sources for local water
supply are difficult to
ensure
Hydraulic Characteristics of Aquifers
Groundwater systems are usually characterised according to their hydraulic properties,
including:
The specific capacity q, given in units L/s/m, which is obtained by dividing the discharge of a
pumped well by the stabilised drawdown at the specific pumping rate that was observed during
the pumping test.
The transmissivity T, given in units of m2/d, which can be considered a measure of the amount of
water that can be transmitted through a rock formation.
The hydraulic conductivity k, given in units m/d, is defined by Darcy’s Law and can be considered
a measure (or a “coefficient”) of the permeability of rock with regard to water.
The yield Q, given in L/s, which refers to the likely or characteristic yield that a well can produce
from a rock formation.
Suggested further reading: Fetter C W (2001): Applied Hydrogeology.- 4th ed. 598 pp; Prentice
Hall; Upper Saddle River, New Jersey.
17
Groundwater Flow Regimes
1
2
3
There are three major types of groundwater flow regimes:
(1) Intergranular flow occurs through the voids (pore space) between individual mineral grains (left picture). This type of flow is typical for rock consisting of unconsolidated deposits (e.g. loose gravel, sand or
sandstore or silt).
(2) In hard rock, groundwater can be transmitted through fissures or fractures. The void space created by
fissures is called “secondary” porosity in contrast to the “primary” porosity referring to the original (unfractured) pore space when the rock was formed. If the primary porosity is small groundwater flow is virtually
restricted to fissures.
(3) Secondary porosity can also be created by dissolution of minerals. As rock dissolves along fractures or
bedding planes large cavities and even caves can develop (right picture). This leads to the development of
“Karst” formations in which groundwater can drain quickly. Karst is usually developed in carbonate rocks
such as limestone and dolomite. Groundwater is often abundant in these formations, but can almost as
easily be polluted as surface streams.
Groundwater Flow
The direction of groundwater movement of
groundwater in the rock is displayed on the
maps by means of arrows and groundwater
contour lines (Figure 21). The arrows indicate
the regional direction of groundwater flow.
The groundwater contours give the elevation
of the groundwater table in meters above sea
level.
18
The groundwater table is the surface that
separates the zone that is saturated with
water from the unsaturated zone above. The
depth of groundwater at a specific point can
be estimated by subtracting the altitude of
the ground surface from the elevation of the
groundwater table.
unsaturated zone before it reaches the groundwater table. Groundwater fills the interconnected open spaces (pores) between mineral
grains and fractures. Groundwater generally
flows from high (in terms of elevation) areas to
low areas. Along topographic sinks it recharges
rivers as base flow as well as lakes and oceans.
Springs and seeps occur where the ground surface intersects the groundwater table or where
groundwater is under pressure and can reach
the surface through fracture zones.
Figure 21: Excerpt of the hydrogeological map
showing groundwater contours (thin blue lines)
and regional flow direction (blue arrows).
Figure 22 explains the occurrence, movement
and circulation of water in the hydrosphere
with emphasis on groundwater. When rain falls
onto the ground surface, a portion infiltrates
into the ground by gravity where it moves both
vertically and laterally depending on the slope.
Infiltrating water first passes through the
Within the mapped area, the Lusaka plateau
forms a 70 km long and 10 km wide ESEWNW stretching low ridge that acts as a local
topographic high dividing the Kafue from the
Chongwe drainage area. The groundwater flow
generally follows the topography with springs
commonly emerging at the plateau’s margins.
Figure 22: Schematic illustration of groundwater flow.
19
2.4. Inset maps
There are two inset maps included in the
1:250,000 map sheet, a sheet map located in
the lower left corner and a second map inside
the body of the main map.
The inset sheet map shows the position and
rectangular extent of the six hydrogeological
maps available for Southern and Lusaka Province in relation with the entire Zambia and
neighbouring countries. A similar inset map
is included in the 1:75,000 map sheets of the
hydrogeological map and vulnerability map of
Lusaka Province.
nant topographic features such as the Kafue
Flats and the Escarpment as well as meteorological stations and the general rainfall pattern. The altitude given in metres above sea
level is displayed as classified colour bands at
100 metre intervals. The rainfall isolines known
as “isohyets” show the distribution of mean
seasonal rainfall in millimetres for the southern and central parts of Zambia. Seasonal rainfall refers to rainfall totals from September to
April. The extent of the hydrogeological map
sheet (body of main map) within the frame of
the inset map is shown as a rectangle bordered
in red colour.
The second inset map (Figure 23) shows a separate thematic map of the topography, domi-
Figure 23: Inset map included in the hydrogeological map 1:250,000 showing
topography and overall rainfall pattern.
20
3. The Vulnerability Map
3.1.
Coverage
The coverage of the vulnerability map corresponds to the map extent of the hydrogeological map at scale 1:75,000. The content of the
vulnerability map comprises:
 topography including roads, villages,
towns, health centres and schools,
 hydrography including rivers and wetlands,
 surface elevation,
 production boreholes of the water supply
utility, and springs,
 groundwater elevation contours and direction of groundwater flow,
 groundwater vulnerability,
 risk areas of potential water quality deterioration, and
 effectiveness of the protective cover and
degree of bypassing (inset maps).
3.2.
Content of Main Map
Apart from the topographic features, hydrology
and groundwater features, described in Chapter 2.3, the following thematic information is
displayed in the vulnerability map.
3.2.1. Risk Areas
The areas with increased risk of groundwater contamination comprise the categories as
shown in Figure 24.
It should be noted that these areas with an
increased risk of being the source of pollution
do not necessarily represent areas with a high
vulnerability. While vulnerability depends on
the characteristics of the natural system, risk
areas are anthropogenic features imposed on
the natural system.
Figure 24: Map symbols for different features with
increased risk of groundwater pollution.
3.2.2. Vulnerability
Groundwater vulnerability describes the sensitivity of groundwater to pollution, or, in other
words, how likely it is that a pollutant originating from the surface reaches the groundwater
table. Vulnerability maps are tools to assess the
ability of the system to protect the groundwater
from contamination. They assist in identifying
areas which need additional protection measures, such as restrictions of human activities.
In areas where vulnerability is high or extreme,
it is not advisable to build infrastructure which
potentially harms groundwater quality (e.g.
sewerage plants, heavy industry, landfills). The
degree of vulnerability is shown in the classes
in Figure 25.
21
layers between the surface and the groundwater table. The I-factor (right inset map) characterizes the infiltration conditions, particularly
the degree to which the protective cover can
be bypassed as a result of lateral surface and
subsurface flow.
Both inset maps have a separate legend while
the main legend includes features that appear
in all three maps.
Figure 25: Map symbols for vulnerability of groundwater (numbers in brackets show the vulnerability
index).
An excerpt of the distribution of the various
vulnerability classes in Lusaka is shown in
Figure 26.
Figure 26: Excerpt of the vulnerability map showing
areas with extreme (red), high (orange) and moderate (yellow) degree of vulnerability.
3.3.
Inset Maps
There are two inset maps in the scale 1:250,000
included in the vulnerability map sheet, located
in the lower left corner and overlapping into
the body of the main map.
The inset maps show the two factors determining the vulnerability of groundwater: the
P- and I-factor [5]. The acronym “P” stands for
protective cover and the “I” stands for infiltration conditions. The P-factor distribution (given
in the left inset map) specifies the effectiveness
of the protective cover resulting mainly from
the thickness and hydraulic properties of the
22
4. References
[1] Akayombokwa, I. & and Mukanda, N. (1998):
Wetland classification for agricultural development in Eastern and Southern Africa: the
Zambian case.- Zambia country paper in:
Food and Agriculture Organization of the
United Nations (FAO): Wetland characterization and classification for sustainable agricultural development, Sub-Regional Office
for East and Southern Africa (SAFR); Harare;
www.fao.org/DOCREP/003/X6611E/x6611e02f.
htm#P2557_115570.
[2] Bäumle R., Neukum Ch., Nkhoma, J. & Silembo,
O. (2007): The groundwater resources of Southern Province, Zambia.- Ministry of Energy and
Water Development - Department of Water
Affairs and Federal Institute for Geosciences
and Natural Resources; Phase 1 Technical
Report Vol. 1 (Nov. 2007) 132 pages and Annex
101pages; Lusaka.
[3] Bäumle R. & Kang’omba, S. (2009): Development of a groundwater information & management program for the Lusaka groundwater
systems, Technical Report No. 2, Desk study &
proposed work program report.- Ministry of
Energy and Water Development - Department
of Water Affairs and Federal Institute for Geosciences and Natural Resources, 101 pages;
Lusaka.
[4] FUGRO Consult GmbH (2011): GeODin Software; www.geodin.com; Berlin, Germany.
[5] Goldscheider, N., Klute, M., Sturm, S. & Hötzl, H.
(2000): The PI-method – a GIS-based approach
to mapping groundwater vulnerability with
special consideration of karst aquifers. – Z.
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